Simultaneous Video Recording to HDD/Card
 

I want to record AVCHD video simultaneously to HDD/memory card or built-in flash memory/memory card, so that I have recorded a back-up of the footage. Is there a consumer grade camera that can do this? I know that the Sony NX5 can do this but it's too expensive.

Is there a way I can plug an external device into my Sony SR11 to recorded simultaneously to the SR11's HDD and the external device, I guess the Nano Flash would allow this but again it's out of my price range.

All help much appreciated!